Scalia also explained that the uber-European-court decided the sodomy issue in Europe; it was not a law passed democratically or a consensus decision by most national high courts.
In other words, judges from a few countries decided the issue for the whole European continent, overriding most national high courts and national parliaments.
You could go on for days about why we should not be relying on foreign law in our cases. The best arguments were made by Scalia, and they are devastating. However, there are some others as well, which are not so devastating, but are nevertheless pretty convincing. One, for example, is this: What the heck does Justice Kennedy know about the law in France or Germany? He's not a French or German lawyer, and he's committing malpractice by pretending that he knows what their laws say.